“Chemists would not routinely rely on the statements of patent lawyers.”
Amgen v. Sandoz, 22-1147 (CAFC, 2023)
Please pardon my delay in posting. I needed to check my wall to see if my diploma was still hanging there. Yes, it is still there. Like many of my fellow patent attorneys, I have a PhD in chemistry. Being a patent attorney and a chemist is not mutually exclusive. To be fair, my laboratory technique might be quite rusty after 20 years behind a desk. But I still consider myself 100% a chemist.
Twice, Amgen’s litigators successfully argued that Amgen’s own patent prosecutors were wrong and should be ignored. First, Amgen persuaded the court to ignore disclosure in the patent application specification regarding purification processes using crystallization. Second, Amgen persuaded the court to ignore statements that their European Council made to the European Patent Office (EPO) regarding which products resulting from Example 2 of Amgen’s U.S. Provisional Application 60/366,515.
Patent attorneys often worry about potential adverse statements that anybody makes during prosecution of patent applications. Keep statements and arguments minimal because, once in writing, you cannot take them back. This case appears to be a rare exception. Depending on whose side you’re on, perhaps it is refreshing that cases such as this show that potentially detrimental statements may be ignored once in a while provided the right evidence.
Otezla® (apremilast) ANDA litigation
Background
Apremalist is an optically pure dextrorotary “(+)” enantiomer of 2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-acetylaminoisoindoline-1,3-dione, having its
stereo center in the “S” conformation. Stereoisomers regarding apremalist are a big deal because of their similarities to thalidomide.
The dispute arose from Sandoz’s filing an Abbreviated New Drug Application (ANDA) to sell a generic version of Amgen’s Otezla® (apremalist), a PDE-4 inhibitor used for treating psoriasis.
Amgen then sued Sandoz to enforce, among others, U S. Patent 7,427,638 claiming a pharmaceutical composition comprising the (+) enantiomer, and U.S. Patent 10,092,541 claims a crystalline solid form of the (+) enantiomer (Form B).
There were several other issues in this opinion. One that I have spent much time considering is the issue of patenting of stereoisomers. Look out for my subsequent post to the page “Obviousness of Stereoisomers & Purified Compounds” regarding the decision in this case.
Priority Claim
U S. Patent 7,893,101 claims priority to earlier provisional patent application 60/366,515. Sandoz argued that the priority claim was invalid because Example 2 in the provisional application, instead of making only crystalline Form B, also made Form C. Sandoz cited as evidence Amgen patent council’s statements to the EPO stating that Example 2 made both forms. However, counsel’s statement was wrong because Example 2 indeed only made Form B. Amgen was allowed to present data to prove it, including thirteen third-party experiments. With the data as evidence, Amgen was able to take back their erroneous, detrimental statement.
Non-Obviousness
Sandoz argued that Amgen’s claims to optically pure compound were obvious because statements in the specification about the separation of the enantiomers. The Statements made the process of isolating enantiomers sound routine. However, Amgen was able to persuade the court that isolating the (+) enantiomer was not routine because, contrary to the specification, formation of chiral salts was not viable. In other words, oversimplified colloquially, the patent attorney drafting the application made the invention sound too easy describing techniques that real chemists would know actually would not work.
